Things look okay. Obviously, playtesting will be needed. How it will really work can only be revealed in Actual Play. So that's your next step to test this part of your game, I think. I'd avoid using the words "fairness" and "balance" in game design. They mean so many different things to so many people and are way to vague in this case to add anything to what you're trying to get across. I'd just start in with tell the GM what to do. Let the social contract take care of fairness.

Thanks for your comments. As it happens, we have a mini-marathon playtest planned for this (extended) weekend, staring Friday night and ending some time Tuesday. I'll post about it in Actual Play sometime afterward.

Interesting point you make on leaving "fairness" out of game design and I suppose you're right. I'm curious, though, why blanket that onto "balance" as well?